The present invention is generally directed to a filter for treatment of an influent. More specifically, the present invention is directed to a synthetic compressible media filter, which may be compressed due to the fluid flow there through.
Wastewater treatment may often comprise multiple stages, often referred to as primary, secondary, and tertiary treatment. While primary treatment may include sedimentation and secondary treatment may reduce dissolved and suspended organic compounds in the wastewater, tertiary treatment may improve effluent quality by removing remaining inorganic components before being discharged back to the environment. Tertiary treatment has included various approaches, including sand filtration, further sedimentation tanks, removal of elements (such as excess nitrogen or phosphorus).
Environmental preservation has inspired governmental administrations to reinforce stringent discharge limit applications on total suspended solids (TSS) and turbidity for effluent nutriment residual from municipal wastewater treatment plants (WWTP) tertiary treatment. TSS and turbidity discharge limitations combined with capital expenditure (CAPEX) and operational expenditure (OPEX) improvements, are the two main drivers for optimization of wastewater tertiary physical treatment. Conventional tertiary filters are organized by four medium characteristics which are cloth, granular, non-granular and membrane. Cloth and single/dual granular medium have filtration rate limits between 3 gpm/ft2 or 7.3 m3/h/m2 and 6 gpm/ft2 or 14.7 m3/h/m2, while membrane filtration ability is constrained by organic loading fouling effects on membrane.
Compressible medium filters have been used to provide varying degrees of wastewater filtration. Compressible medium filters, in general, involve the use of a synthetic compressible porous fiber material (for example, polyvaniladene), rather than a granular media (for example, sand). In accordance with some existing compressible medium filters, the properties of the medium—such as porosity—may be modified by compressing (or releasing) the medium. Such compressible medium filters may be able to achieve increased filtration loading rates. For example, some compressible medium filters have been tested with filtration loading rates up to six times higher (30 gpm/ft2 or 73.3 m3/h/m2) than cloth and granular filters without any additional backwash requirements.
However, in order to provide the ability to compress the medium, the filter medium is generally disposed between two plates, at least one of which may be controllably movable to compress the medium. The mechanical devices necessary to compress the medium may add significant complication to a filtration device, and accordingly cause an increase in the capital expense of building such a filtration device.
Accordingly, it is desirable to provide a filtration device that is as effective or more effective than typical compressible medium filters, without the added complication and cost of compression machinery.